Analysis of fibrous zeolites in the volcanic deposits of the Viterbo Province, Italy

作者：Cattaneo Andrea^*; Rossotti Andrea; Pasquare Giorgio; Somigliana Anna; Cavallo Domenico M

来源：Environmental Earth Sciences, 2011, 63(4): 861-871.

DOI：10.1007/s12665-010-0756-3

• Fibrous zeolites
• Viterbo Province
• Volcanic deposits
• X-ray powder diffraction
• Scanning electron microscopy
• Digital image processing

Since Etrurian age, the Viterbo Province (Central Italy) is famous for its ancient towns carved out of local ignimbrite deposits which geologically represent the sedimentation of pumice-rich, volcano-related pyroclastic flows. Almost the entire study area is geologically characterized by a thick succession of ignimbrites, tephra fallouts and lava flow deposits locally subjected to zeolitization. Among zeolites, fibrous erionite represents a well-known health hazard and so this work aims at locating and quantifying the presence of fibrous zeolites in volcanic deposits of the Viterbo area, suggesting at the same time a standard operational procedure useful in other areas showing the same possible hazard. 41 samples collected in the Viterbo area were analyzed by X-ray powder diffraction, optical and electron microscopy. Fibrous zeolites were detected in five samples and quantified in amounts ranging from 0.35 to 1.66% vol. They generally occur in tetragonal or orthorhombic prismatic habit and showed chemical composition mainly consistent with K-phillipsite. Fibrous zeolites occurred with aspect ratios (mean = 6.3), comparable or lower than those of erionite fibers reported in previous studies and mean diameters > 3 mu m.

• 出版日期2011-6